vshcherb
commented
6 years ago We do have around 30 unit-tests for very different turn-lanes configuration, unfortunately, even adding new one test (for broken scenario) is failing others. Simply saying, today turn:lanes are not enough to properly calculate the display to navigation systems. Yes, we have another issue to add support for motorway_junction to display exit number, so I think it will be implemented earlier.
I think the behaviour of voice and lane instructions at junctions could be improved. Currently, if the driver needs to use a motorway exit, osmand gives the distance to the point "highway:motorway_junction". In most cases (more about later) this is the point where a deceleration lane ENDS (https://wiki.openstreetmap.org/wiki/Lane_assist/Examples/Motorway_exit). This information is not that useful for a driver. He needs to know (preferably by voice) when to switch lanes and for safety reasons, as early as possible so at the BEGINNING of that lane.
Sadly, the lanes and turn:lanes tagging is not available everywhere. In France for example, the point of "highway:motorway_junction" is set to the beginning of a deceleration lane (In this case the voice guidance works well).
Suggestion 1: Osmand should support both ways of mapping:
Search for the point motorway_junction a.) if there is no lane tagging on the segment before let osmand act as it is now doing. (Voice guidance: "Turn slight right") b.) the segment before has a turn:lane tagging: "Go back" to the point where the additional lane is added and use it to calculate the distance. (Voice guidance: "In x meter use (right|left) exit lane to destination)
I fully agree thats not easy to programmatically catch different ways of mapping styles, but in this case i think it would improve a lot. Due to the different voice output an experienced mapper could find places where the tagging is missing and add it later based on sat pictures. Instructions would be more clear on places where 2 exits are very close to each other (https://github.com/osmandapp/Osmand/issues/3788). Instructions would be more consistent because in both cases the driver would get the distance to the point where the exit lane starts.
Suggestion 2: Support destination:lanes This tag seems to be ignored by osmand but could be quite useful in cases where an exit lane splits in multiple ways with different destinations. Espescially with voice guidance this will allow the driver to choose the correct lane without looking at the display.